Evaluation of the Prevalence and Incidence of Pediatric Alopecia Areata Using Electronic Health Record Data

IMPORTANCE Pediatric alopecia areata (AA) prevalence and incidence data are key to understanding the natural history of this medical disease. OBJECTIVE To determine the prevalence and incidence of AA in a pediatric population across time, age, sex, race and ethnicity, and geographic areas within the US. DESIGN, SETTING, AND PARTICIPANTS In this multicenter cohort study conducted among 5 children's hospitals, data (January 2009 to November 2020) were collected from a standardized electronic health record (PEDSnet database, version 4.0) to evaluate the incidence and prevalence of pediatric M. The study cohort included patients younger than 18 years with at least 2 physician visits during which a diagnosis code for AA was recorded, or 1 dermatologist specialty visit for which AA was recorded. MAIN OUTCOMES AND MEASURES The prevalence denominator population comprised 5 409 919 patients. The incidence denominator population was 2 896 241. We identified 5801 children for inclusion in the AA cohort, and 2398 (41.3%) had 12 months or more of follow-up and were included in the incidence analysis. RESULTS Of 5801 patients in the AA cohort, the mean (SD) age was 9.0 (4.5) years, 3259 (562%) were female, 359 (6.2) were Asian, 1094 (18.9%) were Black, 1348 (23.2%) were Hispanic, and 2362 (40.7%) were White. The overall prevalence of pediatric AA was 0.11%, and the participants in the AA cohort were more often older, female, and members of a racial and ethnic minority group than the full PEDSnet population. The 11-year overall incidence rate of pediatric AA between 2009 and 2020 was 13.6 cases per 100 000 person-years (95% CI, 13.1-14.2). The incidence rate by age was normally distributed and peaked at age 6 years. Rates were 22.8% higher in female patients than male patients (15.1 cases per 100 000 person-years for females vs 12.3 cases per 100 000 person-years for males). Additionally, incidence rates were highest among Hispanic children (31.5 cases per 100 000 person-years). CONCLUSIONS AND RELEVANCE This cohort study examined the prevalence and incidence rates of pediatric AA in the US across time, age, sex, race and ethnicity, and region from 2009 to 2020, finding a prevalence of 0.11% (doubling during the last decade) and incidence rate of 13.6 cases per 100 000 person-years. Additionally, the results identified Asian and Hispanic children as high-risk demographic subgroups who were shown to be 2 and 3 times more likely, respectively, to receive a diagnosis of AA.